This invention relates to packages for hermetic encapsulation of piezoelectric components, especially quartz resonators.
As a general practice quartz resonators are encapsulated so that the quartz disk (which has an electrode exposed on each side) is wedged in vertical position between two metal springs which are insulated from a base plate. The metal springs pass through the base plate so that over the base plate is placed a package whose bottom edges are hermetically sealed to the base plate.
The search for piezoelectric components with smaller space requirements and lower production costs has led to flatpacks, in which the quartz resonator is placed horizontally, whereby the two leads are bent in the direction of the printed circuit board (PCB) and are fastened to it. This is known as SMT or surface mounting technology.
Such a flat piezoelectric resonator is described in German Patent DE-OS No. 34 27 548, however the component described therein has disadvantages. For example, a simultaneous vapor deposition of both electrodes on the quartz resonator disk is not possible. This extends production time and makes the production process more difficult. In addition, tuning of the resonance frequency cannot take place simultaneous with deposition of the vapor and a fine tuning of the resonance frequency is not possible after closing of the package.